Reference Values for Weight Loss During 1 Year After Sleeve Gastrectomy: a Multicenter Retrospective Study in Japan

Introduction: This study aimed to provide reference values for the percentage total weight loss during 1 year after laparoscopic sleeve gastrectomy associated with primary response in Japan. Methods: This multicenter retrospective study comprised 248 patients with severe obesity who underwent laparoscopic sleeve gastrectomy at five institutions in Japan. A percentage total weight loss < 20% at 1 year was defined as primary non-response. Parsimonious predictive models were developed based on the results of multiple regression analyses. A receiver operating characteristic curve analysis was used to assess the discriminative performance for primary non-response. Results: The median age, initial body mass index, and percentage total weight loss at 1 year were 41 years, 41.4 kg/m², and 30.1%, respectively. There were 28 (11.3%) primary non-responders. For discriminating primary non-responders, the areas under the receiver operating characteristic curve of the parsimonious model and actual percentage of total weight loss at 3 months after laparoscopic sleeve gastrectomy were 0.846 and 0.803, respectively. Cutoffs for the predicted percentage total weight loss using the model and actual value of percentage total weight loss at 3 months attaining 80% sensitivity were 30% and 22%, and those attaining 98% specificity were 22% and 15%, respectively. Conclusions: Reference values for the percentage total weight loss at 3 months were obtained using the predictive model and actual value of percentage total weight loss at 3 months. Patients at risk for primary non-response can be determined at 3 months with these values, which can help in considering earlier interventions. Graphical abstract: [Figure not available: see fulltext.]